I am in the process of migrating to hibernate3, but I'm currently experiencing a problem in hibernate2. If there is another location I should be going, please let me know.

I'm working with two model objects with independent lifecycles: Agreement and Committee respectively. I am creating a CommitteeAssignment many-to-many entity object to save the following:



Saving one CommitteeAssignment goes all the way to the db, no problems. When I add another and try to save, the transaction attempts to insert both, causing a duplicate key violation.

My setup seems to cause Hibernate not to see the first saved CommitteeAssignment as persistent. I verified by saving the first, and them re-attaching the Agreement object graph with a session.lock() and i got a "cannot lock tranisient instance: CommitteeAssignment" (please NOTE that the object was already saved through to the database.

Here are the players:

in Agreement.hbm.xml....



in CommitteeAssignment



In Committee is the same as in agreement, but with key column of "committee_id"

Thanks in advance.

How do you add the second one? Meanwhile you might want to look into <key-many-to-one ...>, and please put your code parts in a code tag so that it shows up nicely. It's hard to read codes with regular fonts.



Farzad-

Thanks for looking in.

I am adding new CommitteeAssignment objects to both sets (in Agreement and Committee (NOTE: Committee objects already exist in the db and are looked up for each add).

The first process is:

1. new session
2. begin
3. add new CommitteeAssignment to both collections
4. saveOrUpdate(Agreement)
5. commit
6. close session

This saves the first record to committee_assignments in the database.

The second process has the same steps as the first, except with a new CommitteAssignment (same Agreement, different Committee).

This is what triggers the unique key violation on the committee_assignments table. I notice each I add another assignment to make the collection size (n), there are (n) inserts in the sql log file.

Separately, after adding the first assignment to the collection and saved to the db, i've tried locking the Agreement object to re-associate to a new session, and that triggers a "can't lock unsaved transient value: CommitteeAssignment)" exception.

Hibernate can't tell that any of my CommitteeAssignment objects are persisted.

Also to NOTE: I can successfully add any number of assignments in a junit test case, each in different transactions and sessions. Moving into the web tier is where i find the problems. However, I use the same persistence strategy and API in both the test and the web, save for the fact that the web is facilitated by a request listener.

I just can't figure this one out.

Ah that explains everything. unsaved-value="any" makes saveOrUpdate act like save so there will be no update. You can simply remove the setting if you are upgrading to the version 3.



Farzad-

I went with a collection of components since the upgrade to Hibernate3 is a bit off for us.

Thanks Farzad for your feedback!